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The Future of 5G

Making sense of recent developments and what they mean for 5G services and the inbuilding sector.

By Mark Chapman

There has been much recent news and hype about 5G and its role in the evolution of cellular networks. In short, 5G promises ultra high speed, high capacity, low latency and all-pervasive wireless communications while opening up new business models and services. Fulfilling such a wide-ranging set of hopes and expectations is unlikely to be easy, quick or cheap. It is worth stopping to consider what this all means and when 5G services may impact the inbuilding sector.

On the technology front, Qualcomm continues to promote millimeter wave (mmW) bands including 28GHz and 39GHz for high speed, high capacity communications. While this is partially fueled by their need to justify expensive new chips for new markets, the technology behind these innovations is impressive.

QCOM recently announced a millimeter wave antenna reputedly about the size of a dime. The company claims it can fit two such antennas in a smartphone already and aims to shrink them another 50 percent over the next twelve months. Pretty cool stuff.

For their part carriers are keen to impress as to their ability to solve looming capacity problems with new spectrum and high capacity radios. Recently Verizon, Qualcomm Technologies and Novatel Wireless announced work on 5G New Radio (NR) mmW field trials.

More relevant to inbuilding perhaps, is ATT’s recent testing of mmW frequencies in Dallas. According to Fierce Wireless, AT&T submitted paperwork for Special Temporary Authority (STA) with the FCC to demonstrate 5G capabilities and propagation using the 28 and 39 GHz bands at a hotel in Dallas. AT&T noted that its 5G demonstrations will involve communications between fixed base stations placed indoors in a room or open space located inside the building.

David Wolter, AVP of Radio Technology & Architecture at AT&T Labs, told FierceWirelessTech in January that AT&T were interested in the propagation characteristics at millimeter wave, including the interaction with Low E glass, which is highly reflective at millimeter wave. Construction materials also play a role, and there are many variables and factors to consider and quantify. “The materials vary a lot in the impact,” Wolter said. “We’re looking at all of those things to gather data as well as data that’s been public.”

Our take away from this research is that inbuilding mmW research is in its early stages and deployment of in-building 5G networks based on mmW are still some ways off.

Much Support

However, there is much support for deployment of 5G technologies in the lower frequency bands that are currently used for 4G service. Again, Qualcomm is supportive of this parallel track and Dean Brenner, Qualcomm SVP for government affairs, told RCR Wireless News during Mobile World Congress Americas. “We’re on a path here for 5G, and also for gigabit LTE,” he said. “Those are the two mega technology trends that are in the wireless industry…and there’s spectrum implications for both.”

He added, “The key from a spectrum point of view is to make sure there’s low-, mid- and high-band spectrum available, and available in a steady stream. The operators have the financial wherewithal to both acquire the spectrum and deploy it. Back to my two mega-trends–in terms of 5G, you will see spectrum that’s used both in the sub-6 GHz range and in the millimeter wave.”

From this perspective, 5G will be evolutionary not revolutionary, and will likely grow to encompass existing spectrum without necessarily replacing the existing 4G technology. Much will be under the hood as it were – improvements and enhancements to core functionality and the gradual moving of critical components to the edge where latency can be better controlled.

So, behind the hype we see real innovation which will apply to existing spectrum and likely drive the capabilities of existing network equipment and phone in an incremental fashion. 4G will continue to be deployed and new spectrum bands added as they come available. Carrier Aggregation (more pipes into your phone from multiple sources) will add speed and capacity driving phone innovation in advance of 5G technology. In fact it is all likely to blend into one seamless wave of innovation.

This view of 5G encompasses existing networks and considers them as a fabric on which 5G evolves, rather than a rip and replace to a new network. It also means that the carriers who own the majority of spectrum may not be the only interested parties behind provisioning of 5G. While operators will undoubtedly lead and pioneer deployment of advanced 5G services on external networks, there is an increasing realization that inbuilding connectivity is a vital component of the average user experience. There is growing interest from buildings owners and operators in supporting and indeed monetizing this demand, and forward looking owners increasingly view cellular connectivity as a key requirement and an opportunity.

A Potentially Disruptive Factor

One enabling and disruptive factor may be the emergent CBRS (Citizens Broadband Radio System) which uses the 3.5GHz (3550MHz to 3700MHz) spectrum to provide LTE based wireless voice and data service.

Unlike previous spectrum allocations, this is based on an innovative and experimental spectrum-sharing framework intended to improve utilization and spectrum efficiency. While a U.S. initiative, regulators around the world are watching closely with a view to adoption of the principal elements if it proves effective. 5.8 GHZ LAA (License Assisted Access) is a similar shared spectrum approach which is currently being deployed. LAA uses Carrier Aggregation in the downlink to combine LTE in unlicensed spectrum (5 GHz) with LTE in the licensed band. This aggregation of spectrum provides for a fatter pipe with faster data rates, but it does require an anchor in the licensed domain so is primarily of value to existing Mobile Network Operators (MNOs).

A key benefit of both approaches is the use of LTE radio interfaces which can leverage existing technology, chipsets and devices creating huge economies of scale. It is essentially just one more frequency band to support on a multimode device so integration into existing handsets is relatively straightforward and major OEMS are likely to adopt once the business model is proven.

For CBRS, the availability of large swathes of spectrum has excited many potential entrants and the localized nature of the spectrum will allow them to deploy in areas where they expect high loads to provide a complete mobile experience without a massive long term investment in spectrum and infrastructure.

Third-party operators or Neutral Hosts already provide valuable services bridging between the interests of the MNOs and the needs of buildings owners, campuses, large public venues and stadiums, etc. Where cellular coverage is inadequate or underserved these companies deploy custom DAS or small cell-based systems and negotiate with operators to connect these to their networks. However, this model requires the explicit support of the operators as the systems use their licensed frequencies. This requires careful coordination and planning both at project inception and on an ongoing basis as the RF landscape changes.

CBRS offers the opportunity for Neutral Hosts to obtain geographically relevant spectrum on demand and deploy complementary LTE based networks using their “own” spectrum. The key is that all operators could be accommodated on the same spectrum and equipment which significantly improves the business model. It is likely that the MNOs would provide the necessary interconnect and that networks would be interoperable and seamlessly handoff.

A logical extension of the Neutral Host model is for buildings owner/operators to deploy their own systems. CBRS is an opportunity to operate their own spectrum (much like Wi-Fi but without the interference and quality issues) while gaining control over cost and quality. Even better, it affords the opportunity to build a single network capable of multi operator support. They do not have to ask permission to use the spectrum or rely on, or coordinate with, the Operators.

The concept of a Private LTE network is exciting in itself and may lead to other business models. These Private networks enjoy all the benefits of licensed spectrum, but on a restricted geographic basis without having to invest in expensive licenses or custom technology. As in the Neutral Host case it is likely that MNOS would want to provide interconnectivity.

However, CBRS looks much more like an LTE deployment than it does a Wi-Fi system. Access point locations and power levels need to be carefully and professionally designed and planned. Unlike Wi-Fi which is a distributed architecture, LTE derives its spectral efficiency and resilience from a centralized and coordinated approach. With Wi-Fi the usual approach to coverage or speed issues is to slap up another AP. This may locally improve performance but at the expense of overall efficiency and quality and is eventually self defeating.

Care and Feeding

It is likely that professional DAS, Small Cell and inbuilding wireless experts will be in demand for anything but the most trivial installations. These companies design, install, commission and maintain equipment as and when required. Inbuilding networks will inevitably evolve and continue to change over time, requiring ongoing care and feeding.

While CBRS Private Network systems could operate in a completely standalone mode as a localized data service, they will be far more useful and more widely and rapidly adopted if integration with the major cellular networks is supported. In particular, connectivity with mainstream network operators will be critical.

Such integration may be coordinated directly with the carriers, much as it is done with existing DAS and small cell networks, albeit using their own spectrum. However, another opportunity and business model is the establishment of “Micro Roaming Entities”, with the knowledge, skill and scale to aggregate and consolidate traffic. These companies would coordinate with Carriers, supporting seamless roaming by feeding data from smaller stand alone systems through to the major networks.

CBRS promises to revolutionize wireless access, opening the door to new entrants and creating new business models and revenue streams. There is much work to be done and many of the details, particularly the licensing costs and terms are yet to be established. However, this could become a bridge between the licensed and regulated world of cellular and the chaotic world of Wi-Fi, creating ubiquitous high capacity, high quality service in buildings. CBRS also points the way to business models based on spectrum sharing which are likely to extend to 5G and beyond.

5G is yet another step in the ever evolving mobile communications network, offering not only higher speeds and pervasive connectivity, but enabling new and exciting services and business models ranging from smart buildings to smart cities and inter vehicle communications, to name a few.

However, the fact that 80 percent of mobile traffic happens in buildings is lost on no one and any vision of 5G must acknowledge the role of the owners and operators of those spaces. It is increasingly hard for 4G service to reach in building without a dedicated DAS network. Looking forward, the higher frequencies and much more complex technologies associated with 5G makes it even more likely that DAS type systems will become standard.

What seems evident is that relationships between the operators and the building’s owners are likely to strengthen and evolve. Operators will come to view a building not just as another antenna but more as a partner in network extension and connectivity. For their part, buildings owners are likely to view communications and connectivity as a vital service, the oft referenced 4th utility, and seek to provide residents with excellent connectivity, while exploring business models which leverage fact that they effectively own the space and access to the spectrum. So yes, 5G is coming, but 5G reality may in fact rely to a large extent on 5G Realty.